In settings such as heavy oil wells, sand in the pumps is sometimes a significant problem affecting a well's ability to run properly. The usual solution to this problem is to stop production and call in a service rig to clean out the sand, with the result that the well is off production for a day or possibly two. In a cased well equipped with a well head, tubing strings are supported by and suspended from a tubing hanger, and this equipment must be removed to allow the service rig to complete clean-up operations.
U.S. Pat. No. 5,957,198 to Haynes discloses a telescoping joint for use in locating the downhole tools in a well bore without disconnecting the production tubing from the well head, so a service rig may not be required. The conduit and tool are axially displaced, allowing for downward and upward displacement as necessary to assist in well bore clean-up. However, the focus in Haynes appears to be on a zone-isolating tool, as the problems associated with an appropriate joint structure are only tangentially addressed, with little attention directed to means for locking or otherwise controlling the joint. U.S. Pat. No. 6,019,175 to Haynes discloses a slightly modified arrangement, but the focus there is on a complicated tubing hanger apparatus and fluid pressure concerns rather than an appropriate joint structure.